Stability Analysis of Quality Protein Maize Hybrids Qualitative and Quantitative Traits under Heat Stress across Different Environments of Prayagraj District in Central India

Maize, also known as corn (Zea mays .L), is one of the world's most important cereal crops. Maize is the only food cereal crop that can be produced throughout the year and requires a moderate environment to thrive. This study claims to determine whether such a statement is accurate and to examine stability in terms of gene action. The study was carried out in three research sites representative different places in CRF, SHUATS, Prayagraj City at an elevation of 98 meters above sea level at 25.87ON latitude and 81.54 OE longitude. and all the locations has sub-tropical climate with extremes of summer and winter. During winter season especially in month of December and January, temperature drops down to as low as 1-20 C, while during summer the temperature reaches up to 450C (NICMEIT 2022). This experiment was undertaken under Randomized Block Design with three replications for assessing their stability. The mean squares due to genotypes, parents, hybrids, and parent vs. hybrids were very significant for all eighteen quantitative and qualitative characters under study, according to the analysis of variance for diallel analysis (model I method II). A stability study was carried out to determine the grain yield of 45 maize hybrids under three environments (E1, E2 and E3), using Eberhart and Russel model. The analysis of variance for combining ability revealed the mean squares due to general combing ability (GCA) and specific combing ability (SCA) were highly significant for all characters studied. Inbred lines P4, P5 and P2 showed significant to highly significant positive GCA effects on grain yield per plant and its attributes, indicating that both parents were good general combiners for this trait. Four hybrids (P5 X P7, P5 X P6, P4 X P8 and P4 X P5) exhibited significant to highly significant SCA effects for grain yield per plant. The estimates of standard heterosis over the best check (HQPM-5) for grain yield per plant revealed five top cross combinations (P5 X P7, P5 X P6, P4 X P8, P5 X P9 and P4 X P5), exhibiting highly significant positive standard heterosis regarding their high and stable performance across environments. The single cross hybrids over all the environments P5 X P6, P5 X P7 and P4 X P5 were found promising for the majority of characters studied, with high mean performance across environments. Based on a regression coefficient close to unity (βi ≈1) and a non-significant deviation from regression (s2di), indicating their adaptability across all environments investigated, best performing hybrids were identified according to three different environments in E1, E2 and E3 were P1 X P6, P2 X P4, P2 X P6, P2 X P8, P3 X P5, P4 X P5, P4 X P7, P4 X P10, P5 X P6, P5 X P7, P6 X P8, P7 X P8, P7 X P9, regression coefficient near to unity (βi ≈1) and non-significant deviation from regression (s2di) there by indicating its adaptability over all environments, thus indicating stable performance in different environments for most of the characters.